This invention relates to railway track equipment and in particular to a system and method for lubrication of the flanged wheels of rolling stock relative to the track upon which they run. Such systems have been in use for many years and are exemplified, for example, by the Huber et al U.S. Pat. No. 2,238,732 of 04/14/41; the Lutts U.S. Pat. No. 4,214,647 of 07/29/80; and the Lounsberry, Jr. U.S. Pat. No. 4,334,596 of 06/15/82, the disclosures of which patents are incorporated herein by reference.
Systems of the type to which this invention is directed are plagued by the problem of controlling the precise amount of lubricant to be dispensed under all of the varying conditions encountered. For example, the lubricant itself may vary in viscosity from batch-to-batch being stored in the reservoir and this presents problems. Further, the systems are required to operate year round and under varying conditions of temperature so that the lubricant, regardless of its nominal viscosity, will display viscosity variations dependent upon ambient temperature.
Contemporarily, it is considered desirable that the lubricant usually be of relatively high viscosity, e.g., grease, in order for the proper lubrication effect be achieved and since such lubricants will display temperature-sensitivity with respect to viscosity, it is difficult, at best, to so control the lubricating system that the desired amount of lubricant is dispensed in the face of the wide range of temperature conditions to which such systems are subjected.
Accordingly, it is a principal concern of this invention to provide a railway lubricating system and method in which the desired, accurate and proper amount of lubricant is dispensed.
Another object of this invention is to provide a system as above in which the desired amount of lubricant is accurately dispensed irrespective of ambient temperature conditions.
An object of the invention resides in apparatus and method of controlling the amount of lubricant dispensed in a railway lubricating system, which comprises the steps of effecting a test cycle during which lubricant is dispensed in test amount to detect the influence of lubricant viscosity on the system, and then effecting further dispensing cycles each to dispense an accurate and desired amount of lubricant in conformity with the detected influence of lubricant viscosity.
Stated otherwise, it is of concern with respect to this invention to provide a system and method in which an initial setting is made to control the amount of lubricant which is dispensed, such set amount not necessarily being in conformity with the desired amount of lubricant required during a dispensing cycle under the temperature conditions prevailing at the time of setting, in combination with feedback means responsive to lubricant viscosity for altering the value of such initial setting to conform with the desired amount of lubricant to be dispensed under the temperature conditions prevailing at a dispensing time subsequent to the time of setting.
In accord with the above, it is of importance that the pump and drive therefor employed to dispense the lubricant be of a type which may be controlled to assure accuracy of the amount of lubricant dispensed, and that means be provided for detecting the amount of lubricant actually dispensed during a dispensing cycle to provide the necessary feedback by which the control of the pump and its drive is altered to effect dispensing of the desired amount of lubricant.
In accord with this invention, it is preferred that the dispensing pump be of the positive displacement gear type and that the drive means therefor controls the dispensing displacement of the pump, with the dispensing displacement being feedback controlled to assure accuracy of the amount of lubricant dispensed.
Stated otherwise, this invention contemplates controllable drive to a positive displacement pump for each of a sequence of lubricant-dispensing cycles with feedback, determined by the amount of lubricant dispensed during a cycle, for changing the duration of drive for a subsequent cycle in the direction of attaining the desired amount of dispensed lubricant during such subsequent cycle.
Other and further objects of this invention will become apparent as this description proceeds.